Shanghai Key Lab of Protected Horticultural Technology, Forestry and Pomology Research Institute, Shanghai Academy of Agricultural Sciences, Jinqi Road 1000, Fengxian District, Shanghai 201403, China.
Int J Mol Sci. 2024 Oct 22;25(21):11347. doi: 10.3390/ijms252111347.
Flesh firmness is an important quality of pear fruits. Breeding cultivars with suitably low flesh firmness is one of the popular pear breeding goals. At present, SNP markers related to pear flesh firmness and genes affecting flesh firmness are still uncertain. In this study, a QTL analysis was performed, and the result showed that the position of 139.857 cM in lineage group 14 (LG14) had the highest average logarithm of odds (3.41) over two years. This newly discovered locus was identified as a flesh firmness-related QTL (qFirmness-LG14). The 'C/T' SNP was found in corresponding Marker1512129. The 'C' genotype is the high-firmness genotype, which is a dominant trait. The average firmness of fruits with genotype C is 21.4% higher than genotype without the C genotype. Transcriptome profiling was obtained between 'Zaoshengxinshui' and 'Qiushui' at five time points. Three candidate genes in the interval of qFirmness-LG14 might affect firmness. A gene of xyloglucan endotransglucosylase 1 () was upregulated in 'Qiushui' at all five time points. Two transcription factors ( and ) were upregulated in 'Zaoshengxinshui', which might be negative regulatory genes for high flesh firmness. The transcriptome results also isolated a large number of cell wall-related genes (e.g., , , , and ) and transcription factors (e.g., , ). These genes are all potential upstream and downstream genes related to flesh firmness. In conclusion, this study provides valuable insights into the QTLs and molecular mechanisms associated with fruit firmness in .
果肉硬度是梨果实的一个重要品质。选育具有适当低果肉硬度的品种是梨的一个热门育种目标。目前，与梨果肉硬度相关的 SNP 标记和影响果肉硬度的基因仍不确定。本研究进行了 QTL 分析，结果表明在第 14 组（LG14）的 139.857cM 位置两年的平均优势对数（3.41）最高。这个新发现的位点被鉴定为一个与果肉硬度相关的 QTL（qFirmness-LG14）。在相应的 Marker1512129 中发现了“C/T”SNP。“C”基因型是高硬度基因型，是显性性状。基因型为 C 的果实平均硬度比没有 C 基因型的果实高 21.4%。在五个时间点对‘早胜新水’和‘秋月’进行了转录组分析。qFirmness-LG14 区间内的三个候选基因可能影响硬度。木葡聚糖内转葡聚糖酶 1 () 的一个基因在‘秋月’的所有五个时间点都上调。两个转录因子（和）在‘早胜新水’中上调，它们可能是高果肉硬度的负调控基因。转录组结果还分离出大量与细胞壁相关的基因（如、、、和）和转录因子（如、）。这些基因都是与果肉硬度相关的潜在上下游基因。综上所述，本研究为梨果实硬度的 QTL 和分子机制提供了有价值的见解。
